To inform the development of interventions to increase uptake and adherence to antiretroviral therapy (ART), we explored perceptions of ART in semi-structured interviews with 52 men and women from UK black African and black Caribbean communities. Verbatim transcripts were analyzed using framework analysis. Perceptions of ART could be grouped into two categories: doubts about the personal necessity for ART and concerns about potential adverse effects. Doubts about necessity stemmed from feeling well, doubts about the efficacy of ART, religious beliefs and the belief that treatment was futile because it could not cure HIV. Concerns about adverse effects included the fear that attending HIV services and taking treatment would lead to disclosure of HIV, feeling overwhelmed at the prospect of starting treatment soon after diagnosis, fears about side effects and potential long-term effects, and physical repulsion. The findings will facilitate the development of interventions to increase uptake and adherence to ART.